There is a school with 100 students and correspondingly 100 lockers, all of which start off closed. The first student opens every locker and the second students closes every other locker starting with the second (2,4,6...etc..) . The 3rd student changes the state of the lockers numbered (3,6,9.. etc.). The fourth student changes the state of the lockers numbered (4,8,12.. etc..).. This continues until all the 100 students passes along the lockers.. when all the 100 student is done which locker is closed and which locker is in open condition?

TCS, Zoho,